1. Field of the Invention
The present invention relates to the field of near infrared analytical instruments for measuring constituents of materials.
2. Description of the Background Art
The prior art contains a number of devices and processes for measuring constituents of samples such as grains. Such devices are known which measure moisture, protein and oil content utilizing near infrared radiation energy. For example, U.S. Pat. Nos. 4,466,076 and 4,627,008, both to Robert D. Rosenthal, the inventor of the present invention, disclose instruments that can measure constituents of a sample by transmitting near infrared radiation energy through the samples. These near infrared quantitative analysis instruments utilize a phenomenon that certain organic substances absorb energy in the near infrared region of the spectrum. In use, there are certain circumstances under which these instruments do not appear to provide good repeatability, i.e., the ability of the instrument to confirm the reading between subsequent and initial samples from a single batch. Because repeatability generally is checked only at the point of read-out, it is difficult to tell what factors are causing repeatability problems. Identifying repeatability problems can therefore be somewhat difficult. There thus exists a need for a device and method for indicating to a user what factors are causing any repeatability problems which may occur.